Mildred Parten was one of the first to study peer sociability among 2 to 5-year-olds in 1932. Parten noticed a dramatic rise of interactive play with age and concluded that social development includes three stages. Parallel play is the first of three stages of play observed in young children. The other two stages include simple social play (playing and sharing together), and finally cooperative play (different complementary roles; shared purpose). The research by Parten indicated that preschool children prefer groups of two, parallel play was less likely with age, a majority of the kids chose playmates of the same sex and that the most common parallel play activities were sand play along with constructive work. Other findings in her study showed that I.Q. level had little impact, siblings preferred to play with each other, home environment was a big factor, and playing house was the most common form of social play among children. Research indicates that these forms of play emerge in the order suggested by Parten, but they do not form a developmental sequence in which later-appearing ones replace earlier ones. All types coexist during the preschool years. Vygotsky believed that play during childhood created a zone of proximal development of the child and guided in intellectual development. Socioeconomic status appeared to only impact associative play, where British children who were used in the study of low socioeconomic status preferred that type of play. This could be explained due to the fact that those kids had fewer toys and more siblings to share toys with.
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